Henry w



UNITED STATES PATENT OFFICE.

HENRY W. JOHNS, OF BROOKLYN, NEW YORK.

COMPOUND ASBESTUS SHEET FOR ROOFING, 800.

SPECIFICATION forming part of Letters Patent No. 230,945, dated August 10, 1880.

Application filed April 19, 1880.

To all whom it may concern Be it known that I, HENRY YV. JOHNS, of Brooklyn, in the State of New York, have invented anew and useful Improvementin Gom-' poundAsbestus Sheet forRoofiu g, &c., ofwhich the following is such full, clear, and exact description as will enable others skilled in the art to which my invention appertains to make and use the same.

My invention consists otan asbestus sheet or sheathing having a coating on one surface of fibrous asbestus united to the sheathing by silicate of soda.

Sheathing has been made of paper-pulp or wool and asbestus, on which a flocking of asbestus has been fastened by glutinous substances; but such combined sheet was not proof against continued tire.

A11 asbestus sheet or sheathing, which is made from pure asbestus by a well-known method, and is sold on the market as pure as bestus sheathing, is coated on one surface with silicate of soda, and on the silicate of soda, while still soft, is deposited fibrous a-sbestus from which impurities and dust have been re- (No model.)

moved. This may be pressed onto the sheathing part way into the silicate of soda, or left as it is deposited. The silicate of soda, hardening, unites the two and gives a compound sheet indestructible by fire.

The removal of the impurities and dust from the fibrous asbestus permits the fibrous asbestus becoming more securely fastened to the silicate of soda and sheathing on which it is deposited, and enables the parts to be united in a firm manner, as above described.

WVhat I claim as new, and desire to secure by Letters Patent, is-- 1. The compound sheet consisting of asbeslus sheathing united with fibrous asbestus by silicate of soda, substantially as specified and set forth.

2. The pure fibrous asbestus combined with a sheet of sheathing by a glutinous substance, substantially as specified.

HENRY W. JOHNS.

Witnesses: I JOHN W. SHUTE, WM. N. TOSHAOHT. 

